The Broadcom BCM3125 combines an in-band 256-QAM receiver, an out-of-band QPSK receiver and a 4/16-QAM transmitter, providing an integrated set-top box or cable modem front-end solution.

The in-band receiver in the BCM3125 directly samples a 36-44 MHz carrier frequency with a l0-bit A/D converter, which is preceded by a programmable gain amplifier (PGA). The in-band demodulator consists of a quadrature mixer and multi-rate filters that convert the oversampled IF data stream to a baseband complex data stream.